More than 100 sleepy tortoises have been woken after a long winter hibernating - in a giant fridge in South Wales.

Global warming means tortoises are having trouble getting a good sleep during the cold season.

No sooner have they dug down into the ground to hibernate in October than they are roused from their slumbers by the unusually warm weather we often get in January - when they should ideally stay sleeping until the middle of March.

It can, quite literally, kill them.

But now, Ann Ovenstone, from Sully, in the Vale of Glamorgan, has come to the rescue.

Ann, 61, who was awarded the MBE in 2001 for her services to Chelonia, the generic term for tortoises, turtles and terrapins, decided to ensure tortoises in the area get their full five months' sleep - and arranged for 117 to hibernate in a specially-built Hibernaculum in her garden.

And yesterday it was time to rouse them from their long slumber.

Owners who had taken their pets to the Hibernaculum - essentially a walk-in fridge where the temperature is kept at four degrees Celsius, or below - came to collect their drowsy tortoises.

The pets were brought out of their boxes, which were filled with shredded paper, given a warm bath, fed lettuce, and then allowed to roam freely around the garden.

Among them was 50-year-old Tilly, whose owner, Hannah Hamnett, 30, from Rhiwbina, Cardiff, was delighted to see her tortoise emerge refreshed and very hungry.

Hannah, who got Tilly from Ann a year ago, said: 'I love tortoises. Tilly is very gentle and she was having difficulty hibernating due to the weather. That's why I brought her here.'

Hannah added that she was considering buying a small chiller where Tilly could hibernate at home next winter.

Ann, who runs the International Tortoise Association, said that over the past five years, global warming had disturbed the hibernating patterns of tortoises. She said: 'Tortoises naturally hibernate in October when it is cold enough.

'But with global warming it is often unusually warm and wet in January and they come back up.'

She added: 'This is the first year we have used the Hibernaculum to ensure they can hibernate properly.'

The charity has hundreds of members who contribute to the upkeep of the centre, which is staffed by volunteers.

Tortoises can live to be 100 years old or more, which mean many will outlive their owners.

Hannah has already made a will which means that if she dies before Tilly, the tortoise will go to the centre, along with a donation.

The Hibernaculum was partly financed by a tortoise's owner who left money in her will to the charity.